The inflammatory reaction and oxidative stress has been linked with PD. Proinflammatory cytokines promote neurodegeneration or neuroprotection in different animal models. In addition, these cytokines have been reported to increase iNOS expression. With the RT-PCR method we evaluated mRNA levels for IL 1beta, IL6, TNF, IFNgamma, IL-10 and iNOS in the striatum of C57BL/6 mice after MPTP intoxication. The IL1beta mRNA expression rapidly increased and peaked at 6 h. The first increase of mRNA for TNFalpha and IFNgamma was noticed at 6-24 h and the second at the 7th day after MPTP intoxication. Two peaks of IL10 mRNA were seen, immediately (6 h) and at the 3 day post MPTP injection. The peak of mRNA level for IL6 was observed at the 7th day. Expression of mRNA for iNOS peaked at 24 h, started decreasing on the 3rd day, but was still present till the 14th day. Those findings suggest that cytokine network and iNOS may be involved in the development of immune changes accompanying degeneration of the nigrostriatal system.